Note: You need to enable scripting and Javascript in your browser settings to best view and navigate our website. Otherwise, use our keyboard navigation and search page. For keyboard tabbing on this page you can bypass the top menu bar navigation and jump to the page sidebar navigation (if applicable), or jump to the page body. Our print link for screen media is scripted. Your computer's normal print command will print this page. Please contact us if you have difficulty in accessing our web pages.

Resource Assessment & Conservation Engineering (RACE) Division

Groundfish Assessment

Aleutian Islands Bottom Trawl Survey Under Way

Groundfish Assessment Program scientists began the 2006 bottom trawl survey of
Aleutian Islands groundfish and invertebrate resources at the beginning of June,
meeting and setting up the chartered vessels Gladiator and Sea Storm in Dutch
Harbor, Alaska. The survey involves the two vessels sampling 366 assigned stations
between Unimak Pass (long. 165˚W) and Stalemate Bank (170˚40'E) in
waters as deep as 500 m. The Gladiator's 50-day charter is divided into
two legs, while the Sea Storm's 70-day charter is divided into three legs.
Charters begin and end in Dutch Harbor and all other leg breaks will be in Adak.
Scientists will collect information on species composition of catches and biological
data and specimens from the catch.

By Mark Wilkins

Annual Eastern Bering Sea Shelf Bottom Trawl Survey

On 30 May 2006, the fishing vessels Arcturus and Northwest Explorer began charters
lasting 60 days to sample 405 stations on the eastern Bering Sea (EBS) shelf.
This annual bottom trawl survey extends the time series of bottom trawl surveys,
begun in 1971, for collecting data on distribution, abundance, and population
biology of key groundfish, crab, and other invertebrate species within the EBS
continental shelf ecosystem.

The first large-scale survey of the EBS shelf was conducted in 1975 in response
to a need for baseline data to assess the potential impact of proposed offshore
oil exploration and development on fishery resources. During this baseline survey,
sampling was conducted between the 20-m and 200-m isobaths and from the Alaska
Peninsula north to approximately 62°N. The spatial coverage of the annual
surveys varied until 1979 when the most comprehensive survey of the EBS shelf
and continental slope was undertaken in cooperation with the Japan Fisheries
Agency. Subsequent annual bottom trawl surveys have essentially resampled the
stations established during the 1975 shelf survey, with slight modifications
each year.

Commercial groundfish and crab fisheries of the EBS shelf are vital to the Alaska
economy. Results from this survey series are integral elements in the stock assessments
of numerous crab, invertebrate, and groundfish species that are updated annually
by the North Pacific Fishery Management Council per the requirements of the Magnuson-Stevens
Fishery Conservation and Management Act.

Preliminary results from this year's survey show water temperatures are
the coldest since 1999. The pool of water with bottom temperatures less than
2˚C extended all the way into Bristol Bay compared to last year when the
cold pool extended to north of the Pribiloff Islands. Interannual variability
in bottom temperatures is important because it can affect the distribution and
behavior of crab and fish populations.